The invention relates to an apparatus for insertion into the human body and which comprises at least two scanning transducers of which at last one preferably scans in the longitudinal direction, and a needle guide, which can be operated from the outside and used for collecting tissue samples from the human body the needle guide being separate from the other part of the apparatus which for hygiene reasons is covered by a sterile sheath.
When inserted into a patient""s anus, such an apparatus is able to locate the internal organs, such as the prostate. If a sample is to be obtained from the area adjacent the neck of the bladder, it is possible to collect the sample by inserting a needle from the outside, the needle holder being attached to the apparatus as shown in FIG. 1. However this requires that a local anaesthetic is applied to the insertion point of the needle, as the area close to the surface of the skin contains many sensory nerves. It is however desirable to avoid such a local anaesthetic. Accordingly it has been desired to insert the needle through the intestinal wall at the anus, confer FIG. 2, whereby a local anaesthetic is not required, as the internal organs are not that sensitive. At the same time it is desirable that the apparatus is covered by a sterile sheath in use such that subsequent disinfection thereof is avoided, naturally the sterile sheath must not be damaged by the needle guide.
U.S. Pat. No. 4,742,829 describes an ultrasound probe including an array of transducer elements for localizing a biopsy needle to be pushed forward in the longitudinal direction of the probe The applicability of such a probe is very limited if the inner organs of of interest are not positioned in the longitudinal direction of the probe.
The object of the invention is thus to provide an apparatus with a needle guide which cannot damage a sterile sheath and which is more applicable. At the same time the needle is to be in a plane substantially in the longitudinal direction.
An apparatus of the above type is according to tie invention characterised in that the needle guide is retained by being pressed into an inclined recess in the other part of the apparatus after the sterile sheath has been arranged on die apparatus and is retained by means of a needle guide holder. The needle guide is thus attached to the part of the apparatus on the outer side of the sterile sheath such that the needle need not penetrate the sheath, which otherwise would entail that the apparatus should be disinfected after use. Due to the inclined fastening of the needle guide the apparatus is able to collect tissue samples in nearly all directions different from the longitudinal direction and due to the at least two scanning transducers not scanning in the same direction it is possible to locate the needle very precisely in space.
U.S. Pat. No. 5,235,987 illustrates a needle guide holder to be mounted on an ultrasonic scanning bead covered with a disposable sheath. The needle is placed in front of the scanning head and such in apparatus is therefore not suitable for insertion into the human body.
Optionally according to the invention the needle guide may be retained by means of a needle guide holder which is clipped firmly onto the other part of the apparatus after the sterile sheath has been arranged on the apparatus.